1. Field of the Invention
This invention relates to passive seat belt systems for providing automatic crash protection to vehicle occupants.
2. Description of the Prior Art
Passive seat belt systems have been suggested in which the seat belt is automatically positioned about a vehicle occupant before the vehicle is operated, e.g., after the door is closed. Exemplary of such systems are those described in U.S. Pat. Nos. 3,895,822 and 3,897,963 to Seiffert et al. The system disclosed in such patents includes a single diagonal seat belt which is fixed at one end to a portion of the door at a location above the height of and rearward of the occupant's shoulder and has its opposite end attached to a retractor mounted, for example, beneath or to the side of the seat. Upon closing of the door, the seat belt is moved to a position to permit ingress and egress of the occupant. When the door is closed, the belt is moved to a position wherein the occupant is restrained in his seat, with any slack in the belt being taken up by the retractor. The retractor itself typically is of the emergency locking type which permits the belt to be extended and retracted so that the occupant can move freely about in his seat during normal driving conditions, but which locks against further belt extension upon deceleration of the vehicle and/or acceleration of the retractor shaft above a predetermined level.
One problem associated with such passive seat belt system is that complete opening of the door is necessary in order to effect full seat belt travel to the position at which ingress and egress are not restricted. This is particularly troublesome in situations where the door cannot be completely opened such as in "tight" parking spaces, and it may be very difficult for the occupant to egress from the vehicle.
It would be desirable if a simple but effective means were provided to completely move the belt to a forward, out-of-the-way position upon only partial opening of the door.